The present application claims priority upon Japanese Patent Application No. 2002-148269 filed May 22, 2002, which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a printing apparatus, a computer-readable medium, and a printing method. Specifically, the present invention relates to a printing apparatus for predicting the usage amount of recording agent used for printing before performing printing at a predetermined resolution based on image data using the recording agent.
2. Description of the Related Art
In a printing apparatus, a recording agent, such as ink and toner, used for printing is supplied from a container containing a predetermined amount of the agent. When the recording agent runs out because of repetitive printing, printing will be ended before completion of an image. In order to avoid waste of recording paper and/or recording agent, there is a printing apparatus that predicts, in advance, the amount of recording agent that will be used for printing, compares the amount with the remaining amount of recording agent, and determines whether or not it is possible to print.
Here, prediction of the recording agent to be used is made by first expanding input image data to be printed into print data that is just about to be used for printing, and then predicting the usage amount of recording agent used according to that print data.
Here, the print data used for usage amount prediction is generated as binary data necessary for depicting an image by supplying, to a printer driver 90a, image data (image signal that has been read) supplied from, for example, an application program under management of an OS (operating system), and using three basic means, i.e., the rasterizer, the color-correction module, and the halftone module, that the printer driver 90a comprises.
That is, the image data is divided into the three primary colors, i.e., R (red), G (green), and B (blue), by the rasterizer, and RGB bit image data in which rasterization has been performed for each color is obtained. The obtained RGB bit image data is converted so that its resolution matches the resolution for output with the printer. For example, if the image data is bit image data that has been read at a resolution of 360 dpi in both the main-scan direction and the sub-scan direction whereas the printer resolution is 720 dpi in both the main-scan direction and the sub-scan direction, a resolution conversion for generating data for interpolation between each data in the main-scan direction and the sub-scan direction of the image data is performed. The resolution-converted RGB bit image data is subjected to a color-correction process by the color-correction module in order to make the data match the colors for printing, and is converted into CMYK bit image data for printing in K (black), C (cyan), M (magenta), and Y (yellow). Further, after dividing C and M of the CMYK bit image data into C, c and M, m using a dark/light ink division table, a halftone process according to, for example, the dither method or the error diffusion method is performed by the halftone module. In this way, arrangement on a bitmap, for example, is determined for each color, and a binary bitmap is generated respectively.
However, in the printing apparatus described above, since prediction of the recording agent to be used is performed according to print data that is just about to be used for printing, that is, the bitmap in which the color-correction process, the halftone process etc. have been performed with respect to image data that has undergone resolution conversion in order to match the printer resolution. Therefore, much time will be spent for the processes of generating an enormous amount of data that configures the bitmap matching the printer resolution and the processes of predicting the usage amount of recording agent based on such a bitmap. This usage amount prediction is an unnecessary process in the original printing process. That is, if the usage amount of recording agent is less than the remaining amount of recording agent, then it is preferable that the process is performed in the shortest time as possible, since such a process will only cause a delay in printing speed.
The present invention has been made in view of the above problems, and an object thereof is to realize a printing apparatus, a computer-readable medium, and a printing method capable of performing prediction of a usage amount of a recording agent with respect to image data to be printed in a short amount of time.
A main invention is a printing apparatus as follows.
A printing apparatus comprises:
a print head for performing printing using a recording agent; and
a usage amount prediction section for predicting, before printing is performed at a predetermined resolution based on image data using the print head, a usage amount of the recording agent to be used for the printing, wherein, upon predicting the usage amount, the usage amount prediction section uses data based on the image data and having a resolution lower than the predetermined resolution.
Other features of the present invention are made clear by the description below and the accompanying drawings.